1. Field of Invention
The present invention relates generally to seats, including vehicular seats. More particularly, the present invention relates to an adjustable lumbar support for a seat.
2. Description of the Related Art
It is well-recognized that a person sitting in a seat for an extended time period may desire additional support to obtain greater seat comfort and/or alleviate seat discomfort. Vehicle operators, vehicle passengers, and people whose jobs require them to be seated for extended periods of time are typically chief among those individuals who seek such additional support. The support is typically desired to provide greater comfort in the lower or the lumbar region of the back. As used herein, the term “seat” applies to a variety of seat structures, including chairs and vehicular seats.
The discomfort problem has been addressed in the prior art in several ways. A simple, although not complete, solution is to utilize a pillow placed low in the seat against the back thereof. By configuring the pillow into different shapes, a variation in lumbar support can be achieved. More permanent solutions to lumbar support problems have also been addressed, for example, in U.S. Pat. No. 5,076,643 issued to A. Colasanti, et al., on Dec. 31, 1993; and U.S. Pat. No. 5,190,348 issued to A. Colasanti on Mar. 2, 1993.
Both of the devices described in the '643 and '348 patents are of complex construction and require substantial time and cost for fabrication and installation. The requirements for the installation of a mounting plate, as well as the inter-securement of the bladder and plate elements, are primary reasons for the high cost, complexity of construction and the need of substantial time for the manufacture and installation of each device.
Other devices are also known in the art. Among these other devices are those disclosed in U.S. Pat. No. 4,567,615 issued to H. Fanti on Feb. 4, 1986, and U.S. Pat. No. 6,056,360, issued on May 2, 2000, to the predecessor in interest of the assignee of the present application, discloses a lumbar support system comprising unitary and divided leaf members. This device proved to be complicated and costly to manufacture. In addition to providing adjustment of the lumbar support in a horizontal direction, i.e. to increase or decrease the amount of support provided, it is also desirable to provide adjustment of the lumbar support in a vertical direction in order to provide lumbar support over a greater vertical dimension thereby accommodating a wide range of heights among seat occupants. However, the state of the art vertical adjustment merely raises or lowers the “bump” providing the support. What is desired is an adjustment that increases the vertical dimension of the support, thus providing for taller lumbar support, rather than merely increasing the height of the “bump” relative to the occupant's back.